Theoretical analyses indicate that, a channel capacity increases as the number of antennas increases. Further, a better beamforming effect can be obtained as the number of antennas at a transmit end increases. Therefore, a wireless transmission technology with more antennas for transmission and reception, that is, a Multiple-Input Multiple-Output (MIMO) technology, is always one of mainstream technologies studied in the field of mobile communications.
A reference signal, that is, a pilot signal, is a type of known signal provided by a base station to user equipment (UE) and used by the UE for channel estimation or channel measurement. Currently, a basic concept of pilot signal design is that each port corresponds to one pilot signal. For such a one-to-one mapping manner, each antenna omni-directionally transmits one pilot signal.
In the MIMO technology, the number of ports increases as the number of antennas increases. If an existing pilot signal design solution is adopted, the base station needs to send pilot signals to the UE by using all ports, resulting in poor flexibility when the base station configures the pilot signals for the UE. In addition, the UE also needs to measure pilot signals for all the ports, which increases the measurement complexity.